Description Of Advanced Landing Grounds Used During WW 2

Advanced Landing Ground

Experience in North African and Italian Campaigns had shown that
Fighter groups required a runway 120 feet wide x 3,600 feet long,
Fighter-Bombers required a runway 120 feet wide x 5,000 feet long and
Medium Bombers required a runway 120 feet wide x 6,000 feet long.

ALG [Advanced Landing Ground] was a term used/given to the temporary advance airfields constructed by the Allies during WW 2 during the liberation of Europe.

They were built in the UK before the invasion and later in North West Europe from 6 June 1944 to V-E Day 7 May 1945.

Unlike the permanent airfields built in the UK these tactical combat airfields were temporary, used to support the advancing ground armies engaged on the battlefield and when the front line had advanced, left for support units or abandoned.

Instead of using rough, unimproved dirt strips the engineers used surfacing material to strengthen the soil to support the weight of the aircraft and as a measure of insurance against wet weather.

Airfields were initially a single runway, laid down East to West [09/27] unless local conditions dictated a different direction.

Captured airfields could be restored for use as an ALG in 1 to 3 days, depending on the amount of drainage and the number of mines and booby traps they met.

A favourable site an ALG could be constructed, including reconnaissance time, in 1 to 3 days. Less favourable sites, which required more clearing and grading, or an all-weather field, which would require additional infrastructure, would take 3 to 10 days.

ALGs were equipped with access roads, a dump for supplies, ammunition and gasoline drums, and drinking water, along with a minimal electrical grid for communications and station lighting.

Tents were used for accommodation and support facilities, time was the all important factor, the field could serve its purpose if available only for a few days,

As the forward area became the rear, the ALG could be improved for use by medium bombers or transport units.

Putting down a Pierced Steel Planking (PSP) Runway at an Advanced Landing Ground under construction
Ex Ohakea Museum

An unforeseen development was the demand for transport, supply and evacuation airfields as the Allied forces advanced past Paris and toward the German border.

By late 1944 supplies could not keep up with the advancing Armies and construction of airfields suitable for the C-47s became a priority, these brought in ammunition of all types, fuel, and other supplies, and, on the return trip, they evacuated the wounded to the rear for treatment.

By 15th September 1944 the 9th Engineer Command of the USAAF had placed/repaired over 80 airfields, the British Engineers had constructed 76 airfields and the 12th US Engineers from the Mediterranean Theater had built/repaired 20+ fields in Southern France

The stabilization of the front lines in the Netherlands, Belgium and Eastern France in mid-September, which would last into the New Year, allowed a chance to re-organize and prepare for the upcoming winter,

As expected, they couldn’t build new PHS or SMI airstrips during the Autumn rain and Winter snow because of the wet ground conditions.

Besides concrete, the American made PSP was the only available surfacing material that could be laid.

To keep the supply lines open, selected airfields in Belgium and France were ‘Winterized’ with PSP, due to the limited supply of the planking material, only a limited number of airfields could be done.

This, in turn, required 2 Wings/Groups to use the same field, allowing the 2nd TAF and the 9th Air Force to continue flying combat missions as required.

The major problem affecting airfield construction in early 1945 was not the German Ardennes Offensive, which only caused 1 abandonment [Y 39 Haguenau], but the early thaw in February that threatened to make the airfields un-usable due to mud and water.

By using local labour, the Engineers carried out massive maintenance on the threatened airfields and successfully solved the problem.

The renewed offensive following ‘The Battle Of The Bulge’ was supported in earnest by the building of support airfields in Germany.

As the rapid advance through central Germany progressed, scores of former Luftwaffe airfields, both grass and hard paved, were captured, mostly undamaged, removing the need for the ALGs construction.

The relative lack of German opposition in March to May 1945 lessened the need for close air support and made greater demands for supply airstrips for the C-47s and other transport aircraft to re-supply the Army.

By V E Day 9 May 1945, 76 of the 126 airfields made usable East of the Rhine River were strictly for Supply & Evacuation use only.

The main types of surfacing material were

Sommerfield Tracking [ST]

A form of stiffened steel wire mesh, mainly used in the UK

Square - Mesh Track [SMT]

A surfacing material made from heavy wire joined in three-inch squares.

During the first few weeks after the Normandy Landings it was the preferred material due to its light weight.

This allowed the overworked transports to transport sufficient quantity's across the Channel.

An easily worked country a SMT landing field for fighters could be laid like a carpet in approx one week.

Prefabricated Hessian [PBS]

After the initial batch of airfields had been lain using SMT the engineers switched to Prefabricated Hessian [Burlap].

Light and easily transported PBS didn’t create the dust problems associated with SMT,

Delivered in 300 feet rolls 36 and 43 inches wide, PBS was laid in overlapping layers to make a dust-free fair weather surface, it was also common to build airstrips using SMT or PSP and laying PBS over the top.

Pierced Steep Planking [PSP]

To supply an all season durable airfield for the RAF’s 2nd Tactical Air Force and the USAAF 9th Air Force’s medium and light bombers, a fourth type of surfacing, known as PSP or Marsden Matting was introduced on the Normandy bridgehead in July 1944.

It was 20 feet long,[3.0M] 15 inches wide,[380mm] joined together and laid perpendicular to the line of flight.

This was long used in other Theaters, but limited supply and greater weight made it use less common.

A SMT runway could be laid in one week, a PBS would take two weeks, and a PSP could take a month to lay.

Emergency Landing Strips [ELS] and Refueling And Rearming Strips [R&R]

Were often built of sod and earth.

Captured airfields had a wide range of runways from Asphalt, Concrete, Macadam, or Tar Penetrated Macadam.

The proprietaries for the use of PSP changed markedly during the Winters of 1944/45.

With the arrival of bad weather in the shape of winter in the Low Counties, it was found that PHS and SMT strips just sunk into the moist ground.

PSP became the only surfacing material the could handle the local weather conditions.

Many subsequent airfields in Belgium and France were subsequently covered with PSP

The USAAF engineers built 5 types of airfields on the Continent, these were

Emergency Landing Strips [ELS]

These were a roughly graded runway approx 2,000 feet long for emergency wheeled or belly landing of damaged aircraft

Supply & Evacuation [S&E]

A roughly graded runway near the front line, or in the rear, used by C-47’s for transport of supplies and munitions to the front lines and evacuation of casualties to the rear.

Refueling & Rearming [R&R]

Consisting of a runway and marshalling area at each end, designed so aircraft based in the rear could land, be refuelled and rearmed and take off again on a mission without having to return to their home field further in the rear.

Usually sited where they could be expanded to a ALG at a later date

Advanced Landing Ground [ALG]

Either developed from scratch or by expanding a R&R strip, it had the addition of technical and support services to enable it to be used over an extended period of time.

Tactical Air Depots [TAD]

A number of ALGs were expanded into TADs by the addition of hangers, shops, more dispersal areas.

Some were designed from scratch, others from ALGs.

The airfields were all given a code letter and number,

A Series Airfields

Located in France, Used by 9th USAAF Units during the invasion of Normandy
[8 June to Mid July 1944] and during Operation Cobra, the breakout from Normandy starting 25 July to 25 August 1944.

Those in Normandy were mostly de-commissioned after their combat use, others in Central France were used in Various non-combat roles until the end of the war.

Numbered 1 to 99

B Series Airfields

Were built by American or British Combat Engineers for RAF use.

Some of these were also used by the USAAF Troop Carrier Groups and Command and Control Organizations.

Y Series Airfields

Initially built by the 12th USAAF Engineers as part of Operation Dragoon, The invasion of Southern France.

They remained mainly un-coded until coming under the control of the 9th USAAF
Engineering Command Control.

The “Y” series extended into Northern France, Belgium, The Netherlands and Occupied Germany.

“Y” coding continued after the “A” coding reached 99

R Series Airfields

Located on Occupied Germany, there were many more than listed here, mainly used as supply and evacuation airfields that were quickly laid down in Agricultural areas or captured Luftwaffe Airfields.

“R” coding continued after the “Y” coding reached 99

Some Info From

with thanks to son-of-satire for the banner